Fischer-Tropsch synthesis is an effective process for converting synthesis gas containing hydrogen and carbon monoxide, also referred to as syngas, to liquid hydrocarbon fuels. It is well known that Fischer-Tropsch synthesis involves a polymerization reaction beginning with a methylene intermediate to produce a wide distribution of hydrocarbons ranging from light gases to solid wax. Hybrid Fischer-Tropsch catalysts, also referred to interchangeably as “hybrid FT catalysts” or “HFT catalysts,” have been developed containing both a Fischer-Tropsch synthesis component, e.g. cobalt, and an acidic zeolite component which have been found to be capable of limiting chain growth in the polymerization reaction to provide a more desirable product distribution.
Challenges have been encountered in hybrid Fischer-Tropsch catalysts containing cobalt as a result of the strong interaction between the cobalt and the zeolite. These may include lower than desired catalytic activity, lower than desired degree of cobalt reduction and undesirably high methane selectivity. For example, the activity of some hybrid Fischer-Tropsch synthesis catalysts which have been reported is about 0.2 g of C5+/gcat/h (U.S. Pat. Nos. 7,973,087; 7,973,086; 7,943,674; and 7,825,164). Generally, it is preferred that the activity of a catalyst be higher.
Another challenge in the development of improved hybrid Fischer-Tropsch catalysts is the development of catalysts which are active, stable and provide high C5+ productivity. There remains a need for hybrid Fischer-Tropsch catalysts with improved catalytic activity which provides improved productivity in a desired range of product distribution, i.e., C5+.